1. Field of the Invention
This invention relates to a belt hoist wherein a hanging member, such as a hook, is secured to one end portion of a belt extended from a winding member so that a load hooked with the hanging member is hoisted up and down or dragged.
2. Description of the Prior Art
A single-hung type belt hoist having the structure in which the hanging member is secured to one end portion of the belt extended from the winding member has a disadvantage that when the one end portion of the belt is merely secured to the hanging member in a clipping manner, a slippage can be caused at the one end portion of the belt by a load applied to the hanging member that is less than a permissible maximum load, so that the one end portion of the belt is easily fallen out from the hanging member at the clipping portion thereof.
In consideration of this circumstance, the applicant of the present invention previously filed an application for patent (which matured into Japanese Patent No. 2,852,737) (which corresponds to U.S. Pat. No. 6,030,015) for a belt hoist that is so designed that the hanging member is secured to one end portion of the belt through a single winding shaft on which the belt is coiled, to well prevent the one end portion of the belt from being slipped due to the load applied to the hanging member which is less than a permissible maximum load, so as to achieve a firm mounting of the hanging member.
Specifically, the belt hoist of the Japanese Patent No. 2,852,737 has the structure in which a hanging member 102 is secured to one end portion of a belt 100 extended from a winding member through a single winding shaft 101 winding the belt 100 therearound, as shown in FIG. 5. The one end portion of the belt 100 has a first coiling portion 103 coiled to be superposed on the winding shaft 101, a second coiling portion 104 coiled to be superposed on the first coiling portion 103, and the first coiling portion 103 and the second coiling portion 104 are coiled in opposite directions to each other. The hanging member 102 has a press-holding portion 105 to press-hold the second coiling portion 104 in sandwich relation.
In this type of belt hoist, the first coiling portion 103 and the second coiling portion 104 are pulled in the direction for the winding shaft 101 to be tightened by a load applied to the hanging member 102, so that the winding shaft 101 can be coiled up double tightly to prevent the one end of the belt 100 from falling out from the hanging member 102, so as to achieve a firm mount of the hanging member 102.
According to the invention of Japanese Patent No. 2,852,737, although the belt can be prevented from being fallen out due to a load less than the permissible maximum load to achieve the firm mount of the hanging member, since the hanging member is secured to the belt without using any specific fixing means such as bolts and the like, it is desirable to prevent the falling of the belt further reliably, so as to provide further improved safety under load less than the permissible maximum load.
It is the object of the present invention to provide a belt hoist that can prevent the falling of the belt further reliably to provide further improved safety under load less than a permissible maximum load.
The present invention is directed to a novel belt hoist having a hanging member which is secured to one end portion of a belt extended from a winding member via a winding shaft on which the belt is coiled, wherein the winding shaft comprises a first shaft and a second shaft which are spaced in an opposed relation, wherein the one end portion of the belt comprises a first coiling portion coiled on the first shaft to be superposed thereon, a second coiling portion coiled on the first coiling portion to be superposed thereon, a third coiling portion coiled on the second shaft to be superposed thereon, and a fourth coiling portion coiled on the third coiling portion to be superposed thereon, wherein the first coiling portion and the second coiling portion are opposite to each other in a coiling direction and the third coiling portion and the fourth coiling portion are opposite to each other in the coiling direction, and wherein the hanging member has press-holding portions for pressing at least one of the second coiling portion and the fourth coiling portion in sandwich relation therebetween.
According to the present invention, the first coiling portion and the second coiling portion are pulled in the direction for the first shaft to be coiled up by the load applied to the hanging member and the belt, and the third coiling portion and the fourth coiling portion are pulled in the direction for the second shaft to be coiled up by the load applied to the hanging member and the belt. As a result of this, the first shaft and the second shaft are each coiled up double tightly. Further, at least one of the second coiling portion and the fourth coiled portion are pressed in sandwich relation to maintain the coiled state of the belt. By virtue of this, the one end portion of the belt can be further reliably prevented from being fallen out, so that the hanging member can be secured thereto further firmly to provide a further improved safety under load less than a permissible maximum load.
According to the present invention, it is preferable that the first shaft and the second shaft are movable close to or away from each other.
This construction enables the first shaft and the second shaft to move close to each other by the load applied to the first coiling portion coiled on the first shaft to be superposed thereon and the third coiling portion coiled on the second shaft to be superposed thereon, so that the coiling portions of the belt can be held in sandwich relation between the first shaft and the second shaft. By virtue of this, the one end portion of the belt can be further reliably prevented from being fallen out, so that the hanging member can be secured thereto further firmly to provide a further improved safety under load less than a permissible maximum load.